The overall objective of this project is to continue to study comprehensively rheumatoid arthritis (RA) at its earliest stage in younger residents of a large racially-mixed community in order to identify factors of possible etiologic or prognostic importance in this disease. Patients entered into this project are first diagnosed as having inflammatory arthritis by a physician within six months of referral, are under 45 years and residents of Memphis or Shelby County. Control subjects are recruited who match each RA patient and both are studied in detail on entry and during subsequent annual follow-ups. The specific research goals, aimed at understanding the etiology, prognostic factors and best methods of treatment of early RA are: To use epidemiologic, clinical and laboratory methods to better classify early RA at its onset and during subsequent follow-up; To search for evidence of infectious agents associated with onset of early arthritis by means of antibody studies; To evaluate possible endocrine-metabolic abnormalities in RA; To investigate environmental, social and psychological factors associated with the onset or progression of RA; To execute drug therapy trials at an early stage of disease which promises greatest benefit; To develop appropriate analytic methods for such multidisciplinary clinical research projects.